Jefferson National Expansion Memorial

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Template:Infobox protected area The Jefferson National Expansion Memorial is located in St. Louis, Missouri near the start of the Lewis and Clark Expedition. It was designated as a National Memorial by Executive Order 7523, on December 21, 1935, and is maintained by the National Park Service (NPS). The Gateway Arch was authorized on May 17, 1954.

The park was established to commemorate several historical events:

the Louisiana Purchase, and the subsequent westward movement of American explorers and pioneers;
the establishment of the first cathedral and the first civil government west of the Mississippi River;
the debate over slavery raised by the Dred Scott case.

Image:Stlouisarchnps.jpg The memorial site consists of a 91-acre (0.36 km²) park along the Mississippi River on the site of the original city of St. Louis; the Old Courthouse, a former state and federal courthouse which saw the origins of the Dred Scott case; the 45,000-square-foot Museum of Westward Expansion; and the Gateway Arch, a steel catenary arch that has become the city's emblem.

Image:Gateway arch.jpg As the park entered the 21st century it is host to four million visitors each year, three-quarters of which enter the Arch and/or the Old Courthouse.

1 The Gateway Arch
2 Visitor center
3 Tram
4 Observation area
5 Additional photographs
6 History
7 Mathematics of the Arch
8 Stunts
9 References
10 External links

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The Gateway Arch

The Arch, designed by Finnish architect Eero Saarinen, stands 630 feet (192 m) tall, and is 630 feet (192 m) at its widest point. The cross-sections of its legs are equilateral triangles, narrowing from 54 feet (16.5 m) at the base to 17 feet (5.2 m) at the top. Each wall consists of a stainless steel skin covering reinforced concrete from ground level to 300 feet (91 m) or carbon steel and rebar from 300 feet (91 m) to the peak. The interior of the Arch is hollow and contains a unique transport system leading to an observation deck at the top. The interior of the Arch also contains two emergency stairwells in the event of a need to evacuate the Arch or if a problem develops with the tram system.

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Visitor center

Underneath the Arch is a visitor center, entered from a descending outdoor ramp starting at either base. Within the center is the Museum of Westward Expansion, exhibits on the history of the St. Louis riverfront, and tram loading and unloading areas. Tucker Theater, finished in 1968 and renovated 30 years later, has about 285 seats and shows a documentary (Monument to the Dream) on the Arch's construction. Odyssey Theater was completed in 1993 and has 255 seats. It was the first 70 mm film theater to be located within on NPS grounds and operated by the NPS. It runs films from a rotating play list.

Visitors pass through security checkpoints at each entrance to the Arch, before being allowed access to the visitor center. Security was increased as result of a 1997 Congressional mandate to establish a Counter-Terrorism Program at the park. The NPS used the increased funding to purchase magnetometers and x-ray equipment for visitor screening and 25 CCTV cameras scattered throughout the grounds of the memorial.

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Tram

Architect Saarinen died from a brain tumor four years before the Arch was completed. Prior to his death he decided to incorporate a power lift system to obviate the need to climb the 1000-plus stairs. After approaching several elevator companies who failed to come up with a viable method, Saarinen hired college dropout and parking elevator designer Richard Bowser to do the job. Skeptical city fathers gave Bowser only two weeks to submit a design, but he was able to succeed. By 1968 a unique tram system that combined an elevator cable lift system with gimballed cars functionally similar to ferris wheel gondolas had been installed.Image:GatewayArchTramCar.jpg From the visitor center one may move to either base of the Arch and enter the tramway much as one would enter an ordinary elevator, through narrow double doors. Passing through the doors the passengers in groups of five enter a horizontal cylindrical compartment containing five seats and a flat floor. Because of the car shape, the compartments have sloped ceilings which are low enough to force taller riders to lean forward while seated (for this reason it's recommended that the tallest of the five passengers in the car sit in the center seat facing the door). Several of these compartments are linked to form a train. These compartments each individually retain an appropriate level by rotating, which allows them to maintain the correct orientation while the entire train follows curved tracks up one leg of the arch.

There are two separate vertical tramways, one on the north end and the other on the south end of the Arch. The north queue area includes displays which interpret the design and construction of the Gateway Arch; the south queue area includes displays about the St. Louis riverfront during the mid-19th century.

Each tram is made up of eight cars. The trip to the top of the Arch takes four minutes, and the trip back down takes three minutes. The car doors have narrow glass panes, allowing passengers to see the interior of the Arch during the trip.

The tram is operated by the quasi-governmental Bi-State Development Agency under an agreement with the NPS.

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Observation area

Near the top of the arch, a rider will exit the compartment and climb a slight grade to enter the arched observation area. Small windows, almost invisible from the ground, allow views across the Mississippi River and southern Illinois with its prominent Mississippian culture mounds to the east at Cahokia, and the city of Saint Louis and the Great Plains to the west. On a clear day, one can see up to 30 miles.(48 km)

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Additional photographs

The riverfront area as seen from the observation deck.	DigitalGlobe Quickbird satellite image.	Part of the south tramway's entrance doors.	The Arch, from the south
The observation deck as seen from the riverfront area	The Arch, from near the Old Cathedral	The Arch, reflected in the North Basin	The Arch, reflected in the North Basin
The Arch, from the west	The sign at the top of the obeservation deck.	The St. Louis Arch as seen from the lawn.

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History

In 1947, a group of civic leaders held a national competition to select a design for the main portion of the Memorial space. Eero Saarinen won this competition with plans for a 590-foot (180-metre) catenary arch to be placed on the banks of the Mississippi River. However, these plans were modified over the next 15 years, placing the arch on higher ground and adding 40 feet (12 m) in height and width.

Saarinen developed the shape with the help of architectural engineer Hannskarl Bandel. It is not a pure inverted catenary. Saarinen preferred a shape that was slightly elongated and thinner towards the top, a shape that produces a subtle soaring effect, and transfers more of the structure's weight downward rather than outward at the base.

When Saarinen won the competition, the official notification went to his father, architect Eliel Saarinen, who had also submitted an entry. The family celebrated with a bottle of champagne, and two hours later an embarrassed official called to say the winner was, in fact, the younger Saarinen. The elder Saarinen then broke out a second bottle of champagne to celebrate his son's success.

The construction of the Arch began February 12, 1963 and was completed on October 28, 1965, costing less than US$15 million to build. Along with all other historical areas of the National Park Service, the memorial was listed on the National Register of Historic Places on October 15, 1966. Vice President Hubert Humphrey and Secretary of the Interior Stewart Udall dedicated the Arch on May 25, 1968.

In 1984, Congress authorized the enlargement of the Memorial to include up to 100 acres on the east bank of the Mississippi River in East St. Louis, Illinois. Funds were authorized to begin land acquisition, but Congress placed a moratorium upon NPS land acquisitions in fiscal year 1998. The moratorium continued into the 21st century, with expansion becoming less likely because of the construction of a riverboat gaming facility and related amenities.

In 1999, the Arch tram queue areas were completely renovated at a cost of approximately $2.2 million.

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Mathematics of the Arch

The geometric form of the Arch was set by mathematical equations provided to Saarinen by Dr. Hannskarl Bandel. Bruce Detmers and other architects expressed the geometric form in blueprints with this equation:

<math>Y=A \left ( \cosh \frac {X}{L} C- 1 \right ),</math>

or, equivalently

<math>X=\frac {L}{C} \cosh^{-1} \left ( 1+ \frac {Y}{A} \right ), </math>

where

<math>f_c = \mbox{maximum height of centroid (in feet)} = 625.0925</math>

<math>Q_b = \mbox{maximum cross sectional area of arch at base (in sq. feet)} = 1262.6651</math>

<math>Q_t = \mbox{minimum cross sectional area of arch at top (in sq. feet)} = 125.1406</math>

<math>L = \mbox{half width of centroid at the base (in feet)} = 299.2239</math>

</div>

This hyperbolic cosine function is also an inverted catenary function (or close to one) or that which describes a hanging chain.

See the References section of this article for links to in-depth treatments of the arch's geometry.

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Stunts

In 1980 Kenneth Swyers tried to parachute onto the span of the Gateway Arch, planning to jump back off to land on the ground below. Instead, he slid all the way down one leg. His not-so-unexpected demise earned him a Darwin Award.

No less than eleven light aircraft have been successfully piloted beneath the arch, the first on June 22, 1966, when the arch had been completed for less than a year.[1]

In 1984, David Adcock of Houston, Texas, began to scale the arch by means of suction cups on his hands and feet, but he was talked out of continuing after having climbed only 20 feet. The next day he succesfully scaled the 21-story Equitable Building in downtown St. Louis.

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References

St. Louis math teacher William V. Thayer's web pages on arch mathematics[2][3]
Web page for the equations of the Arch on the official website of the Jefferson National Expansion Memorial[4]
1980 Darwin Award
The National Parks: Index 2001–2003. Washington: U.S. Department of the Interior.
Arch timeline from the St. Louis Post-Dispatch (cached)